The present exemplary embodiments relate generally to water treatment. They find particular application in conjunction with electrocoagulation, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiments are also amenable to other like applications.
In water treatment, many different contaminants can be removed more efficiently by using a proper coagulant. The coagulant initiates aggregation of the contaminants to large enough particle sizes for easy removal. Coagulants include, for example, aluminum salts, iron salts, and natural or artificial polyelectrolytes. Typically, the inorganic coagulants are introduced into source water in the form of salts having low concentrations of the actual coagulant ions suspended therein. For example, FeCl3*6H2O is a typical coagulant used with salt water, and which contains less than 21% iron by weight.
Another approach for introducing coagulants, which does not suffer from the above noted inefficiency, is electrocoagulation (EC). In EC, a coagulant is produced by electrochemical dissolution of one or more sacrificial electrodes, such as aluminum electrodes, iron electrodes, or the like, under an applied voltage. Dosing can be varied by changing the applied voltage or speed of source water flow past the electrodes. Other advantages of this method include, but are not limited to, reducing sludge generation, emulsion breaking, and the like.
Even though EC has certain advantages over conventional options, it is not as widely used in the water treatment industry. One reason is the variety of electrochemical reactions that can occur depending on source water quality and applied voltage. Many electrochemical reactions do not affect coagulation, whereby energy is wasted unless the electrochemical reactions are controlled and/or limited. Another reason is the need to allow for a good and rapid mixing of the released coagulant ions into the bulk of the source water. For high salinity liquids, such as sea water or some produced waters, the high conductivity of these liquids causes a high dosing current even at low voltages that requires a highly turbulent flow regime to achieve sufficient mixing.
As a result of the above noted challenges, water treatment systems employing EC are often highly adapted to a specific application and hard to adjust to work for other needs. For example, often times, EC systems include a combined dosing and mixing unit, where the shape of the mixing unit and the location of the electrodes are highly dependent upon the particular applications of the EC systems.
The present disclosure contemplates new and improved systems and/or methods for remedying these, and other, problems.